NavList:

I haven't found time to address this in detail, so I thought I would just open it up for a general discussion.

What are the advantages and disadvantages of possible eLoran systems compared with satLoran? By satLoran, I mean a GPS-like system in Low Earth Orbit (LEO) roughly twenty times closer to ground receivers. And just to emphasize this, eLoran is not "mostly Loran" --it is mostly "e". In other words, it won't "revive" the traditional technology of Loran. It will be fundamentally identical to GPS but using ground-based transmitters. I'll hit one advantage for each to get the ball rolling:

• with satLoran, you get global coverage very quickly and at moderate cost since the navigation payloads can piggyback on other satellite systems. Indeed, the system currently offered on the new Iridium satellites already nearly meets this goal (I hope at least some of you read Richard Langley's article, referenced here).
• eLoran transmitters have a sovereignty advantage. If someone fires a missile at a radio transmitter on your territory, it's clearly an act of war (and that fact is a deterrent against such attacks). By contrast, if someone shoots down a few satellites, the case is less clear; obviously a criminal act, but not so clearly an act of war. On the other hand, cyberattacks are feasible on both types of systems.

What else can you come up with?

Frank Reed
ReedNavigation.com
Conanicut Island USA